Process for operating electric-arc lamps in series.



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- F. M. LEWIS. PROCESS EUR GPERAZMNG BLBGTMG ARG LAMPS, im [LIPLIOATIGN FILED JAN. 20. i908.

CIM/:12242441 C@ 551g it@ Gteau/mg? I @vih/mwen .To whom it may concern:

lie it .known that l, FRANK Mronnnn.

" onto rerun nien-ini. Lewis, or Barrieren ENGLAND, Assienon To GENERAL ELECTRIC COMPANY, A concentric-s ernst' Yorin.

recense non ornnsrrne :enno'rsronno nenes rn snnns.

no. Lesers?.

Speccation'o Letters ate'nt.

Patented muy 21,1908.

"einem application slee novelist ai, nonsens no. seg-csa Divineo and ein application sied. January 2o, less. serial no, einem. y

Lewis, ahsuhect of the King of Great Brit ein, and resident of Prestonville Terrace,

lrighton, England, have invented a new and usci-ul process for Operating Electric-Arc Lamps in Series, of Which the following is a specification. n -f 'lherecess of regulating .are lamps in v.which s unt coils are used is well understood. As the src grows longer, more and kmore current is diverted to the shunt coil until, finally, thev shunt coil is energizedsuhciently to bring into play a force which, acting 'on the carbon controllin mechanism,restores the are vto its fixed an normal length.' The regnletion is effected b playing the shunt ageinst the series ooi'. if such lamps are used in series, each lamp maintains its arclength constant irrespective of the other lumps. Fractically speaking the regulation o'eaoh lem'p is self-contained and no one lamp in the series sots to control the aro length of any other lamp. The arcs are not lrept ci the. some fixed length by any true process of synchronization as between diiier ent lamps. Each lamp stands on its own hottoln as it there Were no other lamps in circuit. ln my process all this is different.

.in accordance with my process, l take an electric are. lanp in which the regulation is effected by eseries coil only, that is to say in which there is no shunt regulating coil. li

mount two or more'such lamps inseries in en electric circuit. ln order that the arcs in the ,several lompe .the series, after the'arcs have once heen struck, may each loe of the semelength no metter What instant of Vtime is selected iorcomparison, it is clearly neceseery, carbon consumption being unlform,

, vthat the armatures which control the carbon lis controlling mechanisms or clutches shall, at I any instant, he 1n the same positionin each lamp.' Nour-l attain the synchronization'of vthe armatures governing the carhon con trolhug mechanisms, in each of the lamps of the series, 1n accordance with my process, not hy a force self-contained. in the 'lamp itself, which yacts irrespective of the other lamps `end which keeps each are of a ixed length,

irrespective of the other arcs. On the contrsry l attain this synchronization oi arma- 1 U tures oy having those lamps of the series,

which have their armatures in the normal or proper position for the 'instant of time we ere considering, determine,.hy means of the are-length which goes with this armature position, such e current iow in the circuit as will exeroisean adequate dierential restoring Jforce upon` the larmature of the lamp which is out of its proper position. rl`he ar meture out of pos1t1on "will thus be pulled into position; its position will be synchronized with that ofthe otherarmatures.

Stated more specifically, l impress a conwhich` the lamps, havingv series re ulating coils' onl are mounted in series and lso oonstruct t e armature-and coil ciench lamp that current strengths which differ essentially are required to equilibrate the arma- .65 stant velectrical potential upon th'e circuit in tures in each of the different positions vit occupies in its travel. it will be plain'then 'that if all the lamps of' the series except one,

say, havetheir armatures in the same position and have each a correspending equal arc-length that thehconstant electrical potentiel impressed upon the series circuit Will cause the flow oi a current sufficient in quantity to keep these'armatures lin the positions which they' occupy. It is equally plain that the current 'flowing in the coil'of the lamp Whose armature is out of pos1tion Will he either essentially greater or essentiallyless than necessary to hold the armature in its position. 'llhere will thus be exercised upon the abnormally positioned armature a differential restoring forceeither in the form of unbalanced mechanical pressure or of unbalanced electromagnetic pull which will bring it back into position.

lNhen l have said thatthe different posi tions of the armature required equilibrating current strengths which are essentially dif'- ferent, l mean vthat thedillerence in equi librating current strengths between any two adjacent positions of the armature is sufficient to cause the differential restoring force called into play to he' adequate to lo the- Work of synchronizing or restoring to its proper position the armature which is out of position. Sincel may employ an armature the attraction on which varies with the square of the current, it will beseen that that current may he essentially different in the sense in which l use the term and yet not 4diiler greatly as'shown by ammeter readings. 0n

the other hand, it is possible .for the currents corresponding to different armature positions to differ somewhat and yet, with the type of armature used, it may happen that the differential force brought into play is insufficient to synchronize the displaced armature; such current-strengths, vunder the terminology which I employ, would not differ essentially.

In executing my process I may so arrange matters that the greatest current will flow in the group of lam s when the arcs have just been struck and t iat the current grows grad ually less as the arcs burn and the armatures move to make up for the consumption of carbon` But since in a constant potential system less current flow corres )onds to a greater arc-length, it is plain that arcs in the several lamps of the group, in my process, while they are all caused to be of equal length at any given instant of time., are also caused to all grow gradually longer as the initial period of arcstriking is departed from. Considering the group of lamps in the series circuit, we tind a group ofarcs each with a given arc length at any given moment and, after the lapse of a little time, each with a little longer arc. There is, as it were', a group variation of arc-length. What is more when the arc of any one lamp of the group, by the 'described operation, grows longer than can be maintained, I prefer to cause the circuit to be broken for the whole group of lamps, so that each lamp, of the group feeds forward its carbon until the carbons Contact and the coils strike all the arcs anew. This arc striking by groups only, as it were, I cffect by a regulation restarter which will be described later on.

In order that the current strengths for different positions of the armature may diii'er essentially and may thus call into play an adequate restoring force to synchronize any displaced armature, I may use electric arc lamps of radically different types, it being understood however that my process is confined to the operation in series of are lamps with series regulating coils only. ThusI may use a type of lamp in which the electromagnetic pull of the coil upon the armature is made to vary in the different armature positions. Or I may use t fpcs of lamps in which the mechanical puli of the armature against the coil is made to vary in its different positions. These results I can also bring about by a variety of mechanisms. It will be necessary here merely to ldescribe a single lamp so that the operation of my`.process may be understood. The lamp which I select will be of the type in which the mechanical pull of the armature against-the, coil is made to change in its travel.

In the drawings :-y-Figure -1 is a side elevation, partly in section, showing a lamp embodying my invention after the arc has just been struck; Fig. 2 is a similar view showarc. Fastened to the lam frame is a pivot 50 upon which I mount a ever 2 connected, at one end, to the core 1 bya link 8 and, at the other end, to a dash pot 9 for the urpose of steadying the movement. Rigi y connected with the lever 2 is an arm 3, at right angles to the lever 2, carrying a weight 4, the arm and Weight constituting a bob.

It will be seen that when the core"1 is in its highest position, after the arc has ,'ust been struck, the bob is to the right of t e center and exercises a force tending to'depress the core. In e'ect the core-is made heavier by the bob in its highest position. When the bob is vertical, it exercises no force upon the lever 2 and the core 1 exercises a downward pull determined by its weight and that of its attached parts. When the core is in its lower position and the'bob is to the left of the vertical, as in Fig. 2, it exercises a pressure tending to raise the core. This, in efi'ect, makes the downward pull of the core `less than that corresponding to its weight and that of its attached parts. the action of the bob, within the limits of the travel of the core, is to make the core-heavier the higher up it is drawn and lighter the lower down it falls. The mechanical pull of the armature against the coil grows greater as the position is approached in which the arc has just been struck. This means that the higher the core position, thestronger the current in the solenoid necessary to hold the core in that position. F or' every position of the core there is a corresponding but essential different equilibrating strength of current.

In other words The differential force called into play upon any armature which is out of position is therefore sufficient to synchronize it.

The construction of electric lamp `which I employ is clearly no feature of my process. I may use lamps of radically different designs and t es so 'long as they regulate by the 'series coi only. On the other hand it is essential, in my process, to have the Series circuit carry a current of constant potential as distinguished from a current of constant magnitude. Such constant-potential current acting on the group of lamps is made to determine the flow ot' essentially different current strengths in the circuit depending upon the mean arc-length, at the moment under consideration, 1n the group of lam s.

This, in turn, causes the production of a if ferential restoring `force upon any lamp in the group whose armature happens to be out of the then mean position, W hen the arc length .of any lamp in the group has reached a ,length which it is initially determined no lamp in the roup shall exceed, the circuit of the group is roken, all the carbone of all the lamps run together, the arcs are again struck find, whenthe current is first turned on,

have an arc-length which diilers from what l' have termed the group-length, a differential. restoring force will be generated to bring the arc-lengthin question back to the group arclength. After a sul'licicnt time, some one of the arc-lengths of the group will have attained a length longer than can be maintained.' 'Immediately all the arcs are extinguished, all the carbone run together, and all the arcs' are struck afresh, so that the described process may be repeated.

lt remains to describe the regulation restarter by which' the lamps ot the group have their arcs simultaneously struck when a single arc grows too long. 'lhe lever 2 is verrtended to the left in a prolongation 10, carrying a pin l5, working in. a slotted linlr lo, at-v tached to the keeper i3, of an electi'omagnet le, in th lamp circuit. The slot in the linlr is of sufficient length for a certain ain-cunt of regulation of the arc by means ci the regulan ing solenoid 5, to take place, without any movement of the keeper, the pin l5 playing between the extremities of the-slot l@ during?J such regulation. j

Let us assume that the parts are inthe po sition which they occupy when no current is on, that is to say with the carbone together,

, the clutches resting on their sto s, the lever 2 lying; inclined with the core wel below the solenoid and the keeper hanging above the electromagnet with the pin at the top oi the slot. When the current is now switched on, it traverses the pair of carbons, the solenoid 5 and the electroinagnet ld. The core is pulled upwards, its end of the rocking lever is raised, thev clutch is pulled up and the are is struck. At hefsame time the other end oi the rockings lever is depressed, the keeper i3 is brought within pulling distance of the electromagnet 14E and is attracted and held by the letter. The distance through which the keeper moves is however smaller than the distance through which the pin on the roching lever moves, so that the pin descends some distance in the slot and the keeper no longer hangs from its limb oi the lever.

-Vlrhat l might term the group regulation of arc-length now 'takes place; the cores drop gradually lower and the pins l5 rise in the slots 16. lf, at any moment, any given are equally true,

of the group is not ol thesaine length as the other arcs, the diilerential restoring force will'be generated. But, after a while, the group-length of vthe are will have gradually grown longer and longer, by which time the pin the head of the slot lo. 'lhereu'pon the core 4in that lamp can drop no further but re mains stationery. The carbon can no longer leed and the are in that lain gets so long as l5 in one of the lamps will have reached 'to 'finally break. lThis brea s the group circuit. fl"he solenoids and electromagnets of the several lain s are no longer traversed by current, so t at the core and keeper in each lamp ot the' group'is released, the core dropping and bringing the clutch into contact 'with a stopso that the upper carbon drops into contact with the lower carbon.

The ,circuit oi the group having thus been re established, the arcs are all struck anew and the cycle of operation is repeated.

Although l have spoken of the tact that the current strength and the group arclength var in' .my process', and while it is true that tlie variation must be suicient to produce the results stated herein, it is as has been abundantly demonstrated in practice, that the variation referred to is not suiiicient to be noticeable by the user in the matter of the steadiness of the illumination or the like.

This application is a division of my appli cation No. 233,628, 'filed November 2l, 1904.

l claim,- V

l. The process of operating a group of elec tric are lamps, each having a series regulating coil but no shunt coil, which consists in connecting them in .series circuit, impressine a constant potential upon the circuit, and generating a differential restoring torce to bring to the mean position the armature of any lamp whose position is displaced with reference to that of the other lamps of the i group, substantially as described.

2. The process of operating a group of elecing coil but no shunt coil, which consists in connecting them in series circuit, impressing:

displaced armature of any lamp of the group,.

substantially as described.

3. The processoi operating a group of electric are lamps, each having' a series regulating coil but no shunt coil, which consist'sin connecting them in series circuit, impressing a constant potential 'upon the circuit, getij crating a differential restoriii force to bring to the mean position the disp aced armature iso ll() tric arc lamps, each having1 a series regulaty of anylarnp in the group, and breaking the circuit of the group, to cause all the lamps to feed and strike their arcs anew, When any given arc of the group has grown longer than a predetermined maximum, substantially as described.

4i The process ol' maintaining a inean are length in a group of electric are lamps which consists in energizing the lamps in series by a constant potential, and causing a differential restoring force to lengthen or shorten the are of any lamp by and in opposition to the deviation or" the arc from the inean length.

5. The process of operating a group of arc lamps in series which consists in impr i constant 'potential on the @ii-cuit ani mi l ing the are Vlength of each olf the lamps in ries to Vary in unison from meinem lo inoinent to thereby gradually rlmnge the rurrent flow, substainially as deserilwl.

In testimony whereof l have signed my l naine lo this specification in thepresence oll two subscribing witnesses.

FRANK 'xllCllrilCL lililffl. Witnesses H. l). JAnnsoN, B. F. lrLLrAns, 

